Pipe thread protector

ABSTRACT

A pneumatically actuated pipe thread protector is disclosed as including a relatively rigid annular boot with an inflatable tube mounted therein. The boot is mounted over and about the portion of a pipe to be protected, and the tube is inflated to frictionally grip the pipe and hold the boot onto the pipe as it is moved about. Valve means for inflating and deflating the tube are recessed within the outer wall of the boot, and the boot preferably has rounded, smooth corners so no sharp edges or projections are provided on the exposed exterior of the ring. Also, the open end of the protector is unobstructed so that a drift pin or other instrument can be dropped through the pipe.

Umted States Patent 11 1 1111 3,858,613 Musslewhite [4 Jan. 7, 1975 PIPE THREAD PROTECTOR 3,473,640 10/1969 Schutz 285/97 x 76 Inventor: L. J. Musslewhite 8315 69th A I 1 Edmonton Alberla Canada ve Primary ExammerCharles A. Ruehl I I Attorney, Agent, or FirmHubbard, Thurman, Turner [22] Flledi July 9, 1973 & Tucker [21] Appl. No.: 377,825 [57] S R C AB T A T Related US. Application Data A pneumatically actuated pipe thread protector is dis- [63] 555 52 11 22 of 179903 Sept 197] closed as including a relatively rigid annular boot with an inflatable tube mounted therein. The boot is mounted over and about the portion of a pipe to be protected, and the tube is inflated to frictionany grip [58] Field Of Search 138/96 R, 96 T; 285/96, ff hold the 9 the We moved 285/97 about. alve means for mflatmg and deflating the tube are recessed within the outer wall of the boot, and the [56] References Cited boot preferably has rounded, smooth corners so no sharp edges or projections are provided on the ex- UNITED STATES PATENTS posed exterior of the ring. Also, the open end of the 1,703,657 /1929 Brown et al 138/96 T protector is unobstructed so that a drift pin or other 2,732,364 1/1956 instrument can be dropped through the pipe. 2,745,438 5/l956 Bloom 138/96 T 3,023,995 3/1962 Hopkins 285/97 x 6 Claims, 5 Drawmg Figures (III!- PATENTED 3,858,613

SHEET 2 BF 2 PIPE THREAD PROTECTOR This is a continuation of application, Ser. No. 179,903, filed Sept. 13, 1971, now abandoned.

This invention relates to pipe thread protectors and in one of its aspects to such a protector that is pneumatically actuated.

Pipe thread protectors are used to protect the threads of a stand of pipe and prevent them from being damaged when the pipe strikes adjacent objects. These protectors have particular application during drilling or production of an oil well where the pipe is being moved from a rack to the well bore and may strike or rub against adjacent pipe or drag the floor of the drilling rig.

During such operations it is often necessary to move a large number of such pipe in a short period of time from the pipe stand to the well bore, and the pipe thread protector should be such that it can be quickly placed about the thread of one pipe being moved, then quickly removed from this pipe and placed about the threads of the next pipe to be moved. Pipe thread protectors in use are generally mechanically actuated and require the insertion of a pin or operation of a mechanical latch by the operator. Such devices do not provide the desired quick placement and removal because of the time required to operate the actuating mechanism or because they require special alignment. Also, these devices are subject to mechanical wear and tear from constant usage and are generally constructed so that the key or mechanical actuating member protrudes in a manner to obstruct the end of the pipe being protected, or projects externally from the protector. Obstructions in the end of the pipe are not desirable because this prevents the passage of a drift pin or other instrument through the pipe. Also, projections from the exterior of the protector can be easily damaged or broken off or are dangerous since the pipe may spin when lifted or otherwise be swung about out of control, and such a projection may strike and seriously injure personnel working about the rig.

Several pneumatically actuated pipe thread protectors have been suggested by the prior art in an attempt to provide a protector which provides quick and easy placement and removal from a pipe and eliminates the problems of mechanically actuated protectors. However, these devices also have inwardly extending bstructions or dangerous outwardly extending projections, or have problems of alignment, and they are not in general use today.

It is thus an object of this invention to provide a pneumatically actuated pipe thread protector which provides for quick placement and removal from about a pipe thread, and which does not have externally projecting valve stems or actuating mechanisms.

It is another object of this invention to provide such a thread protector which does not obstruct the open end of a pipe being protected.

Another object of this invention is to provide such a thread protector in which no exposed sharp edges or corners are provided.

Another object of this invention is to provide such a thread protector which is easily and quickly placed in proper alignment about the threads being protected, and which tightly grips the pipe when actuated to prevent it from falling off the pipe during movement thereof.

Another object of this invention is to provide such a thread protector which is simple and relatively inexpensive to construct, is rugged, and has relatively few parts and no major moving mechanical parts subject to breakage or wear and tear.

Another object of this invention is to provide such a thread protector which includes an inflatable tube and a novel means for rapidly deflating the tube to release the protector from the pipe.

These and other objects of this invention are accomplished according to the illustrated preferred embodiment of this invention by providing a relatively rigid annular boot which includes two inwardly projecting abutment rings, each having an inside diameter of size relative to the outside diameter of a pipe thread to be protected so that the boot may be readily placed about and removed from about the threads without substantial interference. The abutment rings and outer wall of the boot from an annular groove inside the boot, and an inflatable tube is mounted in the annular groove and has a deflated position in which it fits relatively loose about the threads to be protected, and an inflated position in which it frictionally engages the threads with a relatively tight fit. The outer wall of the boot includes at least one opening through it and a valve means for inflating and deflating the tube extends from the interior of the inflatable tube into this opening, but does not extend substantially beyond the outer wall of the boot. Preferably two such openings are provided, and one valve means is provided in one opening for rapidly inflating the tube and a second valve means is provided in the other opening for rapidly deflating the tube. The second valve means preferably includes a special cap with a release button which when actuated permits rapid deflation of the tube.

An annular lip may be provided at one end of the boot to abut the end of the pipe being protected, how ever, it is preferred that the radial thickness of this lip be no greater than the thickness of the end of the pipe so that no obstructions are provided in the end of the pipe.

It is also preferred that the boot be made of relatively rigid rubber with all corners and edges rounded so that no sharp comers or edges are provided. However, it is preferred that the rubber have sufficient coeffecient of friction to aid in preventing the pipe from skidding from the pipe stand, and a fabric reinforcing bond may be provided in the boot to prevent it from deforming or expanding when subject to high forces. Also, the boot is relatively light as compared to prior such boots and need contain no metal reinforcing which can deform and become non-circular.

In the drawings, wherein like reference numerals are used throughout to designate like parts,

FIG. 1 is a perspective view of a threaded pipe with the preferred form of protective boot of this invention mounted about one of its threaded ends;

FIG. 2 is a view partly in elevation and partly in cross section taken along the longitudinal axis of the protector and pipe combination of FIG. 1;

FIG. 3 is a partial sectional view taken as the view in FIG. 2 but showing the tube inflated;

FIG. 4 is a cross-sectional view taken at 4-4 of FIG.

FIG. 5 is an exploded view showing the details of the air release valve.

Referring to FIGS. 1 and 2, the preferred form of thread protector of the invention is illustrated as a circular boot mounted about the threaded end 11a of a pipe 11. Boot 10 is preferably constructed of a ring of relatively hard rubber and is relatively rigid. As illustrated, all exposed corners of the boot are preferably rounded so that no sharp edges are exposed to the exterior of the boot.

Boot 10 is also preferably formed so that it has an outer wall 10a and two inwardly projecting abutment rings 12 and 13 which closely fit about threaded portion 11a of pipe 11 with sufficient clearance between their inside wall and threaded portion 11a to permit boot 10 to be placed about and taken off the end of pipe 11 without substantial interference. For example, threaded portion 1 1a may be slightly tapered outwardly from its end so that the inside walls of rings 12 and 13 are likewise tapered, but have about l 16 inch clearance on a diameter with threaded portion 11a. This arrangement with a relatively close fit permits boot 10 to be easily placed about threaded portion 11a and properly aligned therewith so that the operator is assured that when the required amount of air is admitted into boot 10, that boot 10 will be firmly gripped to thread portion 110.

Lower abutment ring 13 also includes an inwardly projecting annular lip 14 which, when boot 10 is placed about threaded portion 11a, abuts against the end of pipe 11 to prevent the boot from being pushed up beyond the part of threaded portion 1 1a which is to be encircled by boot 10. In order to insure that the open end of pipe 11 remains unobstructed, the radial thickness of lip 14 is no greater than and preferably less than the thickness of the end wall of pipe 11, and extends inwardly substantially no further than necessary to serve its function as a stop and to aid in proper alignment of boot 10.

Also, as illustrated in FIG. 2, an annular groove 15 is formed inside of boot l0 and between abutment rings 12 and 13 and the outer wall of boot 10. A circular, inflatable tube 16 is mounted in groove 15 and when boot 10 is placed on the end of pipe 11, tube 16 surrounds threaded portion 11a with a slight clearance. Tube 16 is made of softer rubber than the rubber that the relatively rigid wall of boot 10 is made of, and includes a relatively thin outer wall 17 and a relatively thicker inner wall 18 connected to wall 17 so that an air chamber 19 is formed between walls 17 and 18. Air chamber 19 is preferably relatively small so that it can be rapidly filled with air and deflated by insertion or removal of a small quantity of air. This insures that the operation of placing boot 10 on and taking it from pipe 11 can be done rapidly. When tube 16 is inflated, the inwardly projecting face of thicker wall 18 bears against and frictionally grips threaded portion 11a, and for this reason is made substantially thicker than wall 17 to insure longer life for tube 16.

Outer wall 10a of boot 10 includes openings 20 and 21 extending through it on opposite sides of boot 10. As illustrated, these openings are preferably larger toward the exterior of wall 10a than they are toward the interior of that wall. Valve means for admitting air into and releasing air from chamber 19 is provided in tube 16 and in the illustrated preferred embodiment includes a valve stem assembly 22 on one side of boot 10 extending from chamber 19 into opening 20 for admitting air into chamber 19, and a separate valve stem assembly 23 located in tube 16 and boot 10 on the opposite side thereof from valve stem 22, and extending from chamber 19 into opening 21 for releasing air under pressure from chamber 19. Valve stem assembly 22 may be a standard inner tube or tubeless tire type valve stem. However, it may be necessary to cut off a portion of the stem to insure that it does not project outwardly beyond wall 10a and is preferably recessed within opening 20, but extends at least into the larger part of the opening to permit an air nozzle to be coupled to it. Valve stem assembly 23 is also made from a standard inner tube or tubeless tire valve stem and modified as described below and illustrated in FIG. 5. It also must be of such length so that it does not project outwardly beyond wall 10a and is preferably recessed in opening 21. Again it extends into the larger part of opening 21. Each of valve stem assemblies 22 and 23 have externally threaded stems 24 which have flanges 24a connected to one end and inside of chamber 19, and stems 24 extend through wall 17 and are secured in an air tight relation with chamber 19 by flanges 24a and nuts 24b screwed onto stems 24 and against the outside of wall 17.

The details of valve stem assembly 23 are shown in FIG. 5. Assembly 23 includes a cylindrical valve stem 24 which is threaded both internally and externally. A standard normally closed valve stem element 25 which has external threads is screwed inside of stem 24, and element 25 includes an operator rod 26 which, when depressed, causes valve element 25 to open to permit air under pressure to flow from tube 16. An internally threaded cylindrical cap 27 is screwed over the top of stem 24 and onto the external threads of stem 24. Cap 27 includes an opening through its center in which an air release button 28 is mounted. Button 28 includes an enlarged disk 29 on the outside of cap 27 and a smaller disk or flange 30 on the inside of cap 29 and seated on the top of rod 26 and connected by a bar 31 to disk 29. Bar 31 is of such length that disk 29 is normally spaced from cap 27 a sufficient distance to permit release button 28 to be depressed which causes rod 26 to be depressed and air to flow from tube 16. The opening in which button 28 is mounted may be sufficiently larger than bar 31 to permit air escaping from tube 16 to pass through this opening, or additional small openings 32 in cap 27 may be provided for this purpose.

Also as illustrated in FIGS. 2 and 4, a ring of reinforcing material 32 such as fabric may be provided within wall 10a to provide strength and to insure that boot 10 does not expand and keeps its circular shape even when subjected to relatively high forces when tube 10 is inflated, or during moving of pipe 11.

Thus, in operation, boot 10 is placed on the end of pipe 11 to be protected so that lip 14 abuts the end of the pipe. During this operation, tube 16 is in a collapsed position as shown in FIG. 2, and because of abutment rings 12 and 13, boot 10 will be properly aligned when lip 14 stops its movement onto the pipe. Air is then admitted to tube 16 and chamber 19 through valve stem assembly 22 and tube 16 is inflated until the inwardly projecting face of its wall 18 frictionally grips threaded portion 11a, as shown in FIG. 3, with sufficient force so that boot 10 will not be knocked off of pipe 11 as it is being moved. An air pressure of 30-40 lbs. is generally sufficient and can be readily provided by a small air compressor or hand pump, although where speed of operation is important,

the air compressor is preferred. In either case, because of the relatively small volume of chamber 19, a relatively small quantity of air will fill and pressurize the chamber to the desired pressure thus insuring rapid inflation. When it is desired to remove boot from pipe 11, then button 28 is depressed, and the air pressure in chamber 19 is relieved so that boot 10 can be removed. Again, since only a small quantity of air need be used, the relieving of chamber 19 is relatively rapid so that boot 10 can be quickly removed from pipe 11 and placed on the end of the next pipe to be moved. Since the exterior surface of boot 10 is smooth with rounded corners, and valve stem assemblies 22 and 23 are recessed in boot 10, no dangerous projecting parts are provided. However, in order to facilitate movement by cable of boot 10 from the derrick back to the pipe rack, a hook (not shown) may be provided extending upwardly from the top of boot 10, i.e., externally from ring 12, but need not project laterally from boot 10. Also, since there are no parts of boot 10 that extend inwardly except lip 14, the open end of pipe 11 is left unobstructed.

As used in the foregoing description and the appended claims, the terms pneumatic and air include pressurized nitrogen or similar gases which can be carried in bottles to a drilling well site and used to pressurize tube 16.

From the foregoing it will be seen that this invention is one well adapted to attain all of the ends and objects hereinabove set forth, together with other advantages which are obvious and which are inherent to the apparatus.

It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of the claims.

As many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

The invention having been described, what is claimed 1. A pneumatically actuated pipe thread protector comprising, in combination: a relatively rigid annular boot made of a rubber-like resilient material, said boot including two spaced apart abutment means for supporting and aligning said thread protector with a relatively loose fit about a portion of a pipe to be protected and forming an annular groove in the interior of said protector, one of said abutment means including an annular lip disposed to abut the end of a pipe being protected and limit the movement of said thread protector along the axis of said pipe, said annular lip extending inwardly toward the center of the pipe substantially no further than the thickness of the end wall of the pipe and the inwardly facing edge of said lip forming a circular opening substantially no smaller than the openings in the end of the pipe to be protected so that said opening in the end of said pipe is left substantially unobstructed when the protector is mounted on the pipe; said boot further including at least two openings each extending through the outer wall of said protector; an inflatable tube mounted in said annular groove, said tube adapted to surround said protected portion and inflatable to and deflatable from a position wherein said tube frictionally engages said portion with a relatively tight fit; a first valve means extending from the interior of said tube and into one of said openings and being substantially recessed within said opening for permitting introduction of air into said inflatable tube; a second valve means extending from the interior of said tube and into another of said openings for permitting removal of air from said inflatable tube whereby.

said protector may be rapidly placed about said portion to be protected, inflated to frictionally grip said portion, and rapidly deflated to release said grip for removal from said portion; and a band of pliable reinforcing material disposed in said boot between said annular groove and the outside wall of said boot for restraining substantial movement of said boot away from said protected portion when air is introduced into said inflatable tube.

2. The thread protector of claim 1 wherein said second valve means is a valve stem that is externally threaded and includes a cap screwed onto said valve stem and a release button mounted in said cap.

3. The thread protector of claim 1 wherein said boot is formed so that all externally exposed corners and edges are rounded.

4. The pipe thread protector of claim 1 wherein said inflatable tube is a circular donut shaped member and includes an air chamber between a relatively thick inner wall and a relatively thin outer wall, said relatively thick inner wall being disposed to frictionally grip the threads to be protected when the protector is mounted on the end of a pipe and having a substantially larger cross-sectional area than said air chamber, and the relatively thick inner wall being substantially thicker than twice the thickness of said relatively thin outer wall.

5. A pneumatically actuated pipe thread protector comprising, in combination: an annular boot made of a rubber-like moldable material and having its outer edges rounded, said boot including an inward facing wall tapered along at least a substantial portion of its length and defining a central opening through the protector into which the portion of the pipe to be protected can be passed with a relatively loose fit, the taper of such wall being such that the diameter of the central opening is largest at the end of said protector into which the end of the pipe to be protected is passed; an annular lip formed on the end of said protector opposite the end into which the pipe to be protected is passed, said annular lip disposed to abut the end of the pipe to be protected and prevent the passage of such pipe entirely through said protector, said annular lip extending inwardly toward the center of said pipe substantially no further than the thickness of the end wall of the pipe and the inwardly facing edge of said lip forming a circular opening substantially no smaller than the opening in the end of the pipe to be protected so that said opening in the end of the pipe is left substantially unobstructed when the protector is mounted on the pipe; an annular air cavity formed in the boot for receiving air to permit the movement of at least a portion of said inward facing wall towards the pipe to be protected so that said movable portion frictionally engages said threads with a relatively tight fit, said boot further including at least two valve passageways each extending from said air cavity through an outward facing wall of said boot; a first valve means for introducing air into said cavity, said first valve means extending from the interior of said cavity and through one of said passageways; a second valve means for exhausting air from said cavity, said second valve means extending from the interior of said cavity and through another of said passageways, the outer ends of said valve means being substantially recessed within said passageways, whereby said protector may be rapidly placed about said portion to be protected, be inflated to frictionally grip said portion, and be rapidly deflated to release said grip for removal from said portion; and a band of pliable reinforcing material disposed in said boot between said cavity and the outside wall of said boot, to restrain substantial movement of said boot away from said portion to be protected when air is introduced into said cavity.

6. The pipe thread protector of claim 5 where each of said passageways terminates at a recessed opening located in the outer surface of the wall through which the passageway extends with said recessed openings having a substantially greater width than said passageways, and wherein each of said first and second valve means comprise elongated valve stems the ends of which extend from one of said passageways into the respective recessed opening, and wherein the valve stem comprising said second valve means includes a release button mounted on its end extending into the respective recessed opening for selectively releasing air from 

1. A pneumatically actuated pipe thread protector comprising, in combination: a relatively rigid annular boot made of a rubberlike resilient material, said boot including two spaced apart abutment means for supporting and aligning said thread protector with a relatively loose fit about a portion of a pipe to be protected and forming an annular groove in the interior of said protector, one of said abutment means including an annular lip disposed to abut the end of a pipe being protected and limit the movement of said thread protector along the axis of said pipe, said annular lip extending inwardly toward the center of the pipe substantially no further than the thickness of the end wall of the pipe and the inwardly facing edge of said lip forming a circular opening substantially no smaller than the openings in the end of the pipe to be protected so that said opening in the end of said pipe is left substantially unobstructed when the protector is mounted on the pipe; said boot further including at least two openings each extending through the outer wall of said protector; an inflatable tube mounted in said annular groove, said tube adapted to surround said protected portion and inflatable to and deflatable from a position wherein said tube frictionally engages said portion with a relatively tight fit; a first valve means extending from the interior of said tube and into one of said openings and being substantially recessed within said opening for permitting introduction of air into said inflatable tube; a second valve means extending from the interior of said tube and into another of said openings for permitting removal of air from said inflatable tube whereby said protector may be rapidly placed about said portion to be protected, inflated to frictionally grip said portion, and rapidly deflated to release said grip for removal from said portion; and a band of pliable reinforcing material disposed in said boot between said annular groove and the outside wall of said boot for restraining substantial movement of said boot away from said protected portion when air is introduced into said inflatable tube.
 2. The thread protector of claim 1 wherein said second valve means is a valve stem that is externally threaded and includes a cap screwed onto said valve stem and a release button mounted in said cap.
 3. The thread protector of claim 1 wherein said boot is formed so that all externally exposed corners and edges are rounded.
 4. The pipe thread protector of claim 1 wherein said inflatable tube is a circular donut shaped member and includes an air chamber between a relatively thick inner wall and a relatively thin outer wall, said relatively thick inner wall being disposed to frictionally grip the threads to be protected when the protector is mounted on the end of a pipe and having a substantially larger cross-sectional area tHan said air chamber, and the relatively thick inner wall being substantially thicker than twice the thickness of said relatively thin outer wall.
 5. A pneumatically actuated pipe thread protector comprising, in combination: an annular boot made of a rubber-like moldable material and having its outer edges rounded, said boot including an inward facing wall tapered along at least a substantial portion of its length and defining a central opening through the protector into which the portion of the pipe to be protected can be passed with a relatively loose fit, the taper of such wall being such that the diameter of the central opening is largest at the end of said protector into which the end of the pipe to be protected is passed; an annular lip formed on the end of said protector opposite the end into which the pipe to be protected is passed, said annular lip disposed to abut the end of the pipe to be protected and prevent the passage of such pipe entirely through said protector, said annular lip extending inwardly toward the center of said pipe substantially no further than the thickness of the end wall of the pipe and the inwardly facing edge of said lip forming a circular opening substantially no smaller than the opening in the end of the pipe to be protected so that said opening in the end of the pipe is left substantially unobstructed when the protector is mounted on the pipe; an annular air cavity formed in the boot for receiving air to permit the movement of at least a portion of said inward facing wall towards the pipe to be protected so that said movable portion frictionally engages said threads with a relatively tight fit, said boot further including at least two valve passageways each extending from said air cavity through an outward facing wall of said boot; a first valve means for introducing air into said cavity, said first valve means extending from the interior of said cavity and through one of said passageways; a second valve means for exhausting air from said cavity, said second valve means extending from the interior of said cavity and through another of said passageways, the outer ends of said valve means being substantially recessed within said passageways, whereby said protector may be rapidly placed about said portion to be protected, be inflated to frictionally grip said portion, and be rapidly deflated to release said grip for removal from said portion; and a band of pliable reinforcing material disposed in said boot between said cavity and the outside wall of said boot, to restrain substantial movement of said boot away from said portion to be protected when air is introduced into said cavity.
 6. The pipe thread protector of claim 5 where each of said passageways terminates at a recessed opening located in the outer surface of the wall through which the passageway extends with said recessed openings having a substantially greater width than said passageways, and wherein each of said first and second valve means comprise elongated valve stems the ends of which extend from one of said passageways into the respective recessed opening, and wherein the valve stem comprising said second valve means includes a release button mounted on its end extending into the respective recessed opening for selectively releasing air from said cavity. 